Ion-induced secondary electron emission behavior of sol–gel-derived MgO thin films used for protective layers in alternating current plasma display panels

Abstract

MgO thin films were prepared using two sols (hydrolyzed sol and stabilized sol) and the ion-induced secondary electron emission behavior of the resultant thin films was investigated. A severe fluctuation in the secondary electron emission current was found in MgO films from hydrolyzed sol. The instability of the ion-induced current was due to the nanosized pores, which were formed during the topotactic reaction of Mg(OH)2 to MgO. Nonhydrolyzed MgO films, however, showed a stable ion-induced current. The ion-induced secondary electron emission coefficients (γi) of the MgO films had a maximum of 0.95±0.02 when the films were heat treated at 550 °C in O2. The change in γi of nonhydrolyzed films was discussed from the viewpoint of crystallinity, residual organics, and surface roughness. The high γi and low processing temperature of nonhydrolyzed MgO films revealed that the sol–gel process is suitable to prepare MgO films for use as a protective layer in ac plasma display panel cells.